Hindered phenolic-containing organotin stabilizer for polymers



United States Patent US. Cl. 26045.75 3 Claims ABSTRACT OF THE DISCLOSURE Novel organotin compounds are provided for stabilizing synthetic resins against degradation by thermal oxidation, said compounds having the formula wherein R is selected from the group consisting of alkyl of from 1 to 18 carbon atoms, cycloalkyl, aryl, and benzyl, R is alkyl of from 1 to 12 carbon atoms, x and y each are integers of from 1 to 3 inclusive, and z is an integer of from 0 to 2 inclusive, at least one R group being adjacent to OH group in the phenolic group, and stabilized synthetic resins having incorporated therein an inhibiting amount of said organotin compounds.

This invention relates to novel organotin compounds, to the preparation of such compounds, and to synthetic resins stabilized with said organotin compounds.

It is known that certain organic compounds may be added as antioxidants to synthetic resins which are subject to deterioration from heat. For example, phenols alkylated to protect phenolic groups, of relatively low molecular weight are used commonly as such antioxidants. However, these known antioxidants may be characterized by unsatisfactory stabilizing ability because of thermal decomposition, volatilization, and sublimation during the process of producng films, fibers, or other molded articles. In addition, poor compatibility of the antioxidants with synthetic resins may cause plating-out, blooming, or bleeding phenomenon.

According to the present invention, these adverse effects may be reduced or eliminated by employing a new class of organotin compounds as stabilizers.

It is an object of this invention to provide novel organotin compounds and methods of producing such compounds. A further object of this invention is to provide synthetic resins stabilized with one or more of these novel organotin compounds. Other objects will be apparent to those skilled in the art from the following description.

In accordance with certain of its aspects, the method of this invention for stabilizing synthetic resins against degradation by thermal oxidaton comprises incorporating with said resin an inhibiting amount of a compound having the following formula R is alkyl of from 1 to 12 carbon atoms, x and y each are integers of from 1 to '3 inclusive, and z is an integer of from Q to 2, inclusive, .at least .oneR' group. being-adjacent. a

to OH group in the phenolic group.

3,511,803 Patented May 5, 1970 In accordance with certain aspects of this invention, organotin compounds included in Formula I may be prepared by heating a compound of the formula )y wherein R, z, and y are as defined above with a tri-, di-, or mono-organotin oxide (or alkoxide) in an inert solvent medium such as benzene, toluene, etc. Other compounds Within the general Formula I may be prepared by heating an alkali metal salt of carboxylic acid of Formula a with an organotin halide in alcohol, benzene, or toluene, and removing the formed alkali metal halide from the reaction system.

The novel organotin compounds obtained of this invention may be colorless to light yellow, crystalline or non-crystallinesubstances, depending upon the-Rand R radicals, and the value of x, y, and z in the general Formula I. The compounds may be soluble in those general organic solvents which have a boiling point in the range of 40 to 300 C., e.g. aromatic hydrocarbons, alcohols, ethers, esters, ketones, petroleum hydrocarbon, etc.

Typical examples of compounds of Formula I are:

wherein 1 stands for tertiary.

The low volatility of these organotin compounds may be known in the following table designated as Table I:

TABLE I Organotin compound:

These organotin antioxidants and stabilizers may be combined with or incorporated into the synthetic resins in several ways. For instance, the organotin compound or mixture of compounds may be added to the synthetic resins prior to polymerization. After the addition of the organotin compound, the admixture may be polymerized and molded into films, fibers, or other articles. Alternatively, the organotin compound may be added to the synthetic resin together with other additives such as anabove 170 C., and the amount used must be increased to be effective. Said organotin compounds are also profitable in that the effects of a plurality of said organotin compounds and already known stabilizers are synergistic in their stabilizing efiects: said organotin compounds with sulfur-containing compounds as a peroxide decomposer on polyolefin, and said organotin compounds with di- EXAMPLE 1 Nought point two percent by weight of dibutyltin-bis- (fi-3,5-di-tertiary butyl-4-hydroxy phenyl propionate) [of aforesaid Formula 2] as an antioxidant was added to polyvinyl chloride resin composition containing 2% by weight of dibutyltin maleate as a stabilizer, and 2% by weight of butyl stearate as a mold lubricant, and after milling for 15 minutes on a mixing roll at surface tem perature of 160 C. the mixture was made into a sheet 1 mm. thick. The sheet was then put in a Geer oven at 180 C. for 80 minutes for the heat stability test. The same tests for heat stability were directed to a comparison sheet without the addition of an antioxidant, and one with 0.2% by weight of 2,6-di-tertiary butyl phenol as an antioxidant. In like manner were such tests made for sheets with tribasic lead sulphate in place of dibutyltin maleate as a stabilizer. This data is listed on the following table for other stabilizer, an ultraviolet light absorber, a coloring the different combinations of Stabilizing agents- TABLE II Color After- Initial Stabilizer Antioxidant Color Minutes 80 Minutes Dibutyltin maleate N Light; yellow.- Yellow Light brown.

D0 2,6-di-t-butyl-4-methyl phenol.-- Colorless Light yellow Yellow. D0. Compound of Formula 2 do Colorless Light; yellow. Tri-baslc lead sulphate N one White Light yellow- Brown.

D 2,6-dl-t-butyl-4-methyl phenol do do Li ht b wn, Do Compound of Formula 2 do White White.

agent, a mold lubricant, etc. by mixers, e.g. a ribbon EXAMPLE 2 blender, a high-speed mixer, etc. after which the mixture may be molded into films, fibers, or other articles.

Only an inhibiting amount of organotin compound is required. Preferably, the amount of the organotin stabilizers and antioxidants to be employed in the process of this invention is in the range of 0.01% to 5% by weight based on the weight of the synthetic resins, which will vary depending upon the kind of molded articles and the manner in which the organotin compounds are added.

The organotin compounds of this invention are especially useful in the production of the synthetic resins when these resins are molded or polymerized at a relatively high temperature. Often conventional stabilizers and anti-oxidants sublime from resins at temperatures A two-component synergistic antioxidation mixture of 0.2% by weight of dioctyltin-bis-(ti-3,5-di-tertiary butyl- 4-hydroxy phenyl propionate) [of aforesaid Formula 5] and 0.4% by weight of dilaurylthiodipropionate was added to polyethylene, and after milling for 10 minutes on a mixing roll at surface temperature of 180 C. the mixture was made into a sheet 1 mm. thick. The sheet was then pressed at C. to get even surface, and was put in a Geer oven at C. for the heat stability test. Comparison sheets with the addition of a single antioxidant of dioctyltin-bis-( 3-3,5 di-tertiary butyl-4-hydroxy phenyl propionate), and without any antioxidant were putto the same tests. Results are shown in Table III.

TABLE 111 Antioxidant After 20 Hours After 100 Hours After 400 Hours After 600 Hours None Cracked Cracked Cracked and yellowed... Cracked and yellowed. Dioetyltin-bis-(fl-S fi-di-tertiary butyl-4-hydroxy phenyl Not deteriorated Not deteriorated Not deteriorated Cracked. Didgt y li i ii (5-3 Edi-tertiary butyl--hydroxy phenyi do do do N at deteriorated.

propionate) and dilaurylthiodipropionate.

EXAMPLE 3 agitation. When the mixture began to foam, it was poured into a corrugated cardboard container. The foamed poly-' urethane was then exposed to sunlight and weathering out TABLE IV t i t After 20 Hours After 100 Hours After 400 Hours After 600 Hours None Cracked Cracked DlOCtYltlIl-blS-(Bw fidi-tertiary butyl-4-hydroxy phenyl propionate) Not deteriorated" Not deteriorated. l l d bl l:::II: crmlggdu D1octylt1n-b1s-(fl-3 Mir-tertiary buty thydrrmy phenyl propionate) d ..do Not deteriorated. Not deteriorated dilaurylthiodipropionate.

EXAMPLE 4 doors, and the color of the foam was observed with the ABS resin containing 0.5% by weight of dibutyltinbis-(3,5-di-tertiary butyl-4-hydroxy *benzoate) [of aforesaid Formula 4] as stabilizer was injection molded into a fiat plate 2 mm. thick by conventional method. During the process said ABS resin composition was subjected to heat at 190 C. for 6 minutes. The plate obtained white was put in a Geer oven at 180 C. for 90 minutes with the result of no discoloration.

For purposes of comparison, a fiat plat eof ABS resin without the addition of any stabilizers, and a plate with 0.5% by weight of 2,6-di-tertiary butyl phenol as stabilizer were tested for heat stability by the same procedure as above. The former became yellow immediately after injection molded, and became brown after 60 minutes in a Geer oven. The latter was white immediately after injection molded, and became light yellow after 30 minutes in a Geer oven, yellow after 60 minutes, and brown after 90 minutes.

EXAMPLE Polystyrene containing 0.6% by Weight of dibutyltinbis-(3,5-di-tertiary butyl-4-hydroxy benzoate) [of aforesaid Formlua 4] as stabilizer was injection molded into a fiat plate by conventional method (heat career of 180 C./5 minutes). The plate obtained was colorless and transparent, and was not discolored after allowed to stand in a room for two years. A flat plate of polystyrene without the addition of any stabilizer, which was prepared by the same procedure as above for comparison was clear light yellow in color when molded, and turned yellow with markedly lowered transparency after allowed to stand in room for two years.

EXAMPLE 6 To polycarbonate was added 0.5% by weight of diocty1 tin-bis-(3,5-di-tertiary butyl-4-hydroxy benzoate). The composition was injection molded into a disk by conventional method. In this case the polycarbonate composition was exposed to heat at 260 C. for 10 minutes. The disk obtained was colorless and transparent. For comparison, a disk of polycarbonate without any additives was prepared under similar conditions. The disk obtained was light brown.

EXAMPLE 7 One hundred parts of polyoxypropylene triol (GP-3025,

Mitsui Chme. Ind. Co., Ltd., Japan),

0.35 parts of stannous octoate (T-9, M&T Chemicals Inc.),

1.5 parts of surface active agent (L-520, Union Carbide Corporation) 0.1 parts of triethylenediamine (DABCO, Houndry Process & Chemical Company),

4.5 parts of water, and

0.08 to 0.8 part of dibenzyltin-bis-(fi-3,5-di-tertiary butyl- 4-hydroxy phenyl propionate) were mixed thoroughly with gentle stirring, and 54.5 parts of tolylene diisocyanate (80/20) added with vigorous result as follows.

TABLE V Exposed for Cone. of Antioxidant (Part) 3 Days 7 Days Blank Yellow Yellowish brown 0.08 Light yellow. Light yellow. 0.16 White D 0.40.. 0.80..

wherein R is selected from the group consisting of alkyl of from 1 to 18 carbon atoms, cycloalkyl, aryl, and benzyl, R is alkyl of from 1 to 12 carbon atoms, x and y each are integers of from 1 to 3 inclusive, and z is an lnteger of from 0 to 2 inclusive, at least one R group being adjacent to OH group in the phenolic group.

2. A stabilized synthetic resin composition comprislng a polyolefin, and an inhibiting amount of a 2-component mixture consisting of a compound of the formula wherein R is selected from the group consisting of alkyl of from 1 to 18 carbon atoms, cycloalkyl, aryl, and benzyl, R is alkyl of from 1 to 12 carbon atoms, x and y each y each are integers of from 1 to 3 inclusive, and z is an integer of from 0 to 2 inclusive, at least one R group being adjacent to OH group in the phenolic group, and dilauryl thiodipropionate.

3. A stabilized synthetic resin composition comprising a polyvinyl chloride, and an inhibiting amount of a 2- component mixture consisting of a compound of the formula wherein R is selected from the group consisting of alkyl of from 1 to 18 carbon atoms, cycloalkyl, aryl, and benzyl,

' 7 R is an alkyl of from 1 to 12 carbon atoms, 2 and y each are fiitegers'offrom 1'to 3i11c1usive, arid z is an integer of'from'O t0 Zinclusiv'e; at'least'one R group being adjaent to -OH -gr'oup in thephenolic grofip, and 'an'a1 ready known stabilizer selected from the group consisting of dibutyltin maleate and tribasic lead sulfate.

2,727,917 12/195'5 'Mac k et a1. 260 429 2 182,635.97 3/1258. ,.Gl0skey., 260T429.1 ......v

2,868,765 1/1959 Haefner et a1. 26045.75

" ii: b 3325 8 Naylor etal, 260-4595 Bavley et a1. 260-4535 Dorfelt et a1. 260429.7 Leebrick" 26045.'75

FOREIGN PATENTS Great Britain.

P ima Exam ne -0, V. P HOKE, Assistant Examiner, 

